Exhaust muffler



sept. 2, 1958 INVENToR. Cafll///v C. E. NELSON EXHAUST MUFFLEP;

Filed Dec. 30, 1955 ,Sv wh/ Sv\wm7 Sw* @www L Jm, Lim

`00000Q000 @@QQQQ@ QKHWH NI :00000000000 @00000000.9000 W 1. +,.wwwmdi,0.000000000 000000000005000 0090000000000000000000000 LSNIM dwqenwl QQG mw am n ww@ QW @l u@ mm wwwa *RLIN United ybrutes Patent EXHAUST MUFIFLER Application December 30, 1955, Serial No. 556,568

4 Ciaims. (Ci. 181-53) The present invention relates to a novel muffler structure `of the type adapted to be used in connectio-n with internal combustion engines.

An important object of the present invention is to provide a novel muier structure which may be relatively easily and economically assembled and which has improved functional characteristics.

A more specific object of the presentl invention is to provide a novel muffler structure including a` plurality of tubes and partitions or bafiies'disposed within a body member, which tubes and bafiies are constructed and arranged so as mutually to support each other within and out of Contact with the body member so as tov facilitate assembly thereof within thebody member.

Another more speciiic object of-the present invention is to provide a novel exhaust muffler of the above described type which is constructed so as to promoter the ow of substantial portions of the exhaust gases along and against the outer body member for more effective cooling of the gases.

Other `objects and advantages of the present invention will become apparent from the following description and the accompanying drawings, wherein:

Fig. 1 is an enlarged sectional viewtaken along line 1--1 in Fig. 2 and showing the novel muffier structure of the present invention;

Fig. 2 is a cross-sectional view taken along line 2-2 in Fig. l; and

Fig. 3 is a cross-sectional view taken along line 3--3 in Fig. 1.

Referring now more specifically to the drawings wherein like parts are designated by the same numerals throughout the various tigures, a muiiier ystructure 1.0, incorporating the features of the present invention-comprises an elongated outer tubular body or shell 12 which preferably has an oval transverse cross-sectional shape. End members 14 and 16 close opposite ends yof the body member and are respectively provided with peripheral flanges 18 and 20 welded to the body member. An exhaust inlet tube 22 projects through an opening in the end member 1d defined by an axially extending flange 24 and is welded to this flange. The tube 22 also extends through baffles 26 and 2S spaced longitudinally within the body member and defining opposite end chambers 30 and 32 and a relatively long intermediate chamber 34. As shown in the drawings, openings in the baffie members for receiving the tube 22 are respectively defined by axially extending flanges 36 and 33 which Iclosely encircle the tube. The inner end of the tube 22 opens into the chamber 32 adjacent the end member 16. The mufiier structure is also provided with an outlet tube 40 which projects through an opening in the end member 16 and is welded to an axially extending flange 42 defining this opening. The tube 4th also extends through openings in the baflie members, which openings are respectively defined by flanges 44 and 46 closely encircling the tube.

In order to promote easier and more economical assembly of the tube and battles, it should be noted that the baffles are provided with an oval configuration similar to the cro-ss-sectional shape ofthe tubular body member and have their peripheries 4t and 50 :spaced wellwithin the inner surface of the tubular body member. Thus, there is no need for holding the dimensions -of thebaffles to close tolerances and they may be easily inserted within the tubular body. It should further be noted vthat the batiie 26 is rigidly `connected to the tube 22 by welding the ange 36 to the tube as indicated at 52 while at the same time the tube 40 extends through the ange 44with a slip tit and is not welded or otherwise secured thereto.

Simiiariy the tube 40 is welded tothe ange 46 of the bafiie 28 as at Siand the tube 22 extends through the flange 3S with a slip fit. This structure not only facilitates assemblies of the various parts but also substantially reduces or eliminates stresses which might be imposed 0n the mumer structure as a result of unevenheating and cooling of the body 12 and the tubes and resulting uneven expansion and contraction thereof during operation of the muflier.

It will be appreciated that with the. structure thus far described, the exhaust gases entering the tube 22will empty into the chamber 32 adjacent the outlet end of the muffler. The periphery 50 of the baflie 28 defines in combination with the tubular body member a generally annular or oval passageway 56 between the chambers 32 and 34 and the periphery of the baiiie 26 defines a similar oval or generally annular passageway 5S between the chambers 30 and 34. Thus, the exhaust gases entering the chamber 32 are directed outwardly against the interior surface of the tubular body 12 and flow through the passageway 56 into the chamber 34 from which the gases flow through the passageway 58 into the chamber 30 and finally from the muier structure through the `outlet tube 40. The arrangement of the passageways 56 and 58 insures that a substantial portion of the gases will be directed along the tubular `body 12, which being exposed to the surrounding atmosphere, is relatively cooland promotes cooling of the gases. y.Such cooling of the gases promotes expansion thereof as they pass from the relatively restricted tube 22 through. the chambersy and thus improves the attenuation of the sound impulses and the mutliing characteristics of the structure.

A portion 60 of the inlet tube 22 which extends inwardly from the baie 26 is provided with a plurality of perforations 62 throughout its length and similarly, a portion 64 of the tube 40 which extends inwardiy from the baffle 28 is provided with a-plurality of perforations 66. Thus portions of the gases may pass through perforations 62 into the chamber 34 and from the chamber 34 through the perforatio-ns 66 and out through the tube 40 so that more rapid expansion of at least portions of the gases may occur and thus reduce the back pressure created within the mufiier structure. Furthermore, gas flow may occur between a number of the perforations in 'both tubes and in both forward and reverse directions as pressure pulsations from the internal combustion engine are transmitted to the muiiier structure so that a plurality of paths of gas fiow of different lengths and different directions are provided to promote out-of-phasing and deadening of gas and pressure pulsations and sound resonance. Preferably the chambers 39 and 32 are relatively short as compared with the intermediate chamber 34, and portions 68 and 70 of the tubes 21. and 4d respectively extcnding through these end chambers are imperforate. This arrangement prevents portions of the gases from passing directly from the inlet tube into the open end of the outlet tube and from the open end of the inlet tube directly into the outlet tube while at the same time major portions of the tube are perforated to promote expansion of the gases and out-of-phasing of the impulses in the manner described above.

While the preferred embodiment of the present invention has been shown and described herein, it is obvious that many structural details may be changed without departing from the spirit and scope of the appended claims.

The invention is claimed as follows:

' 1. An exhaust muffler comprising an elongated tubular body, first and second end members respectively secured to and closing opposite ends of said body, first and second tubes respectively secured to and projecting through said first and second end members and respe-ctively having inner end portions opening adjacent said sec-ond and first end members, and a plurality of axially spaced bafes substantially concentric with said body and defining a plurality of chambers within said body, each of said baffles having a peripheral configuration similar to and smaller than a transverse cross sectional configuration of said body and having a free unsupported peripheral edge entirely spaced from an interior surface of -said body and defining therewith a generally annular gas passageway directly between adjacent chambers, said tubes extending through each of said baffles and being respectively secured to a bafiie adjacent their associated end members, said bafiies and said tubes mutually supporting each other away from the interior surface of said body, said tubes providing the only support for said bafes.

2. An exhaust muffler comprising an elongated tubular body, first and second end members respectively secured to and closing opposite ends of said body, first and second substantially parallel perforated tubes respectively secured to and projecting through said first and second end members and respectively having inner end portions opening adjacent said second and first end members, andtfirst and second baffles substantially concentric with said body and respectively disposed adjacent to and spaced from said first and second end members and dening a plurality of chambers within said body, each of said baffles having a peripheral configuration smaller than a transverse cross sectional configuration of said lbody and a free peripheral edge entirely spaced from an interior surface of said body and defining therewith a generally annular gas passageway between adjacent chambers, said first tube extending through both of said baffles and being secured to said first baffle, said second tube extending through both of said baflies and being secured to said second baie, said bafiies and said tubes mutually supporting each other away from the interior surface of said body, said tubes providing the only support for said baffles.

3. An exhaust mufller comprising an elongated tubular body having a generally oval transverse `cross section, first and second end members respectively secured to and closing opposite ends of said body, first and second generally oval baies substantially concentric with said body and respectively disposed adjacent to and spaced from said first and second end members and defining relatively short opposite end chambers and a relatively long intermediate chamber within said body, said bafiies being substantially smaller than the oval cross section of said body and having free peripheral edges entirely spaced from an interior surface of said body and defining therewith generally oval passageways directly between adjacent chambers, a rst tube having an imperforate portion secured to and extending through said rst end member and extending to and secured to said first Ibaffle and a perforated portion extending through said intermediate chamber and into said second bafiie with a slip t, and a second tube having an imperforate port-ion secured to and extending through said second end member and extending to and secured to said second baffle and a perforated portion extending through said intermediate chamber and into said first baffle with a slip fit, said baiiies and said tubes mutually supporting each other away from the interior surface of said body, said tubes providing the only support for said bafiies.

4. An exhaust muffler comprising an elongated tubular body, first and second end members respectively secured to and closing opposite ends of said body, first and second baes substantially concentric with said lbody and respectively disposed adjacent to and spaced from said first and second end members and defining relatively short opposite end chambers and a relatively long intermediate chamber within said body, said bafiies being substantially smaller than a transverse cross section of said body and having free peripheral edges spaced entirely from an inner surface of said body and defining therewith generally annular gas passageways directly between adjacent chambers, a first tube extending through said rst end member and said baflies and secured to said first end member and said first baie, a second tube extending through said second end member and said baffles and secured to said second end member and said second baffle, said tubes having perforated portions extending through said intermediate chamber, said baffles and said tubes mutually supporting each other away from the interior surface of said body, said tubes providing the only support for said baes.

References Cited in the file of this patent UNITED STATES PATENTS 2,100,030 Haas Nov. 23, 1937 2,144,725 Manning I an. 24, 1939 2,675,088 McLeod Apr. 13, 1954 

